Knowing the atomic structures of large biological molecules allows us to begin to understand some of the complex chemical processes taking place inside living organisms. The techniques of X-ray diffraction analysis are being used to work out the atomic structures of some of these biological molecules, especially ones deemed biochemically or clinically important. Based on interpretation of these structures rational drug design and protein engineering are beginning to be possible so we can chemically synthesize not just find cures for diseases. A major practical difficulty with X-ray diffraction analysis is crystal size, quality and durability. To help compensate for crystal problems one needs the most efficient possible instrumentation for measuring the X-ray data. In particular one needs accurate, sensitive, photon-counting, position=sensitive area detectors and we build such detectors. Our design is based on that of the very successful detectors used in the U.C. San Diego (NIH) Research Resource. During Phase I we worked out modifications to the design to ruggedize and simplify manufacture of these detectors. During Phase II we intend to package the detector into a more complete commercial diffractometer system and develop a larger and much faster version of our present detector design to allow use of even smaller poorer crystals thus allowing clinical and biochemical work to proceed which would have been possible before.